In recent years, imaging apparatuses capable of image plane phase difference autofocusing (AF) have been put into practical use. Such an imaging apparatus obtains two phase difference images with phase difference pixels provided in the imaging plane, and performs autofocusing by detecting the distance to the focus position in accordance with the difference in deviation between the two phase difference images.
For example, Patent Document 1 discloses an imaging device that includes opening masks provided for at least some of the photoelectric conversion elements in one-to-one correspondence, so as to output at least two parallax images.